/*
 * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifndef SKY_ENGINE_WTF_HEXNUMBER_H_
#define SKY_ENGINE_WTF_HEXNUMBER_H_

#include "flutter/sky/engine/wtf/text/StringConcatenate.h"

namespace WTF {

enum HexConversionMode { Lowercase, Uppercase };

namespace Internal {

const LChar lowerHexDigits[17] = "0123456789abcdef";
const LChar upperHexDigits[17] = "0123456789ABCDEF";
inline const LChar* hexDigitsForMode(HexConversionMode mode) {
  return mode == Lowercase ? lowerHexDigits : upperHexDigits;
}

};  // namespace Internal

template <typename T>
inline void appendByteAsHex(unsigned char byte,
                            T& destination,
                            HexConversionMode mode = Uppercase) {
  const LChar* hexDigits = Internal::hexDigitsForMode(mode);
  destination.append(hexDigits[byte >> 4]);
  destination.append(hexDigits[byte & 0xF]);
}

template <typename T>
inline void placeByteAsHexCompressIfPossible(
    unsigned char byte,
    T& destination,
    unsigned& index,
    HexConversionMode mode = Uppercase) {
  const LChar* hexDigits = Internal::hexDigitsForMode(mode);
  if (byte >= 0x10)
    destination[index++] = hexDigits[byte >> 4];
  destination[index++] = hexDigits[byte & 0xF];
}

template <typename T>
inline void placeByteAsHex(unsigned char byte,
                           T& destination,
                           HexConversionMode mode = Uppercase) {
  const LChar* hexDigits = Internal::hexDigitsForMode(mode);
  *destination++ = hexDigits[byte >> 4];
  *destination++ = hexDigits[byte & 0xF];
}

template <typename T>
inline void appendUnsignedAsHex(unsigned number,
                                T& destination,
                                HexConversionMode mode = Uppercase) {
  const LChar* hexDigits = Internal::hexDigitsForMode(mode);
  Vector<LChar, 8> result;
  do {
    result.prepend(hexDigits[number % 16]);
    number >>= 4;
  } while (number > 0);

  destination.append(result.data(), result.size());
}

// Same as appendUnsignedAsHex, but using exactly 'desiredDigits' for the
// conversion.
template <typename T>
inline void appendUnsignedAsHexFixedSize(unsigned number,
                                         T& destination,
                                         unsigned desiredDigits,
                                         HexConversionMode mode = Uppercase) {
  ASSERT(desiredDigits);

  const LChar* hexDigits = Internal::hexDigitsForMode(mode);
  Vector<LChar, 8> result;
  do {
    result.prepend(hexDigits[number % 16]);
    number >>= 4;
  } while (result.size() < desiredDigits);

  ASSERT(result.size() == desiredDigits);
  destination.append(result.data(), result.size());
}

}  // namespace WTF

using WTF::Lowercase;
using WTF::appendByteAsHex;
using WTF::appendUnsignedAsHex;
using WTF::appendUnsignedAsHexFixedSize;
using WTF::placeByteAsHex;
using WTF::placeByteAsHexCompressIfPossible;

#endif  // SKY_ENGINE_WTF_HEXNUMBER_H_
